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A new species, Achnanthidium bratanense, is described from Lake Bratan, located on the island of Bali (Indonesia). The morphology of this species was analyzed with light (LM) and scanning electron microscopy (SEM). A. bratanense is characterized by linear-elliptic to nearly elliptic valves with convex margins and rounded, broadly subcapitate apices. The striae of this species are hardly discernable under LM; they are weakly radiate throughout the valve and composed of one to four large transapically elongated areolae of different length and shape. The most similar taxon to A. bratanense is A. macrocephalum, a species described from Sumatra, another Indonesian island. The differences of A. bratanense from similar taxa are discussed. [ABSTRACT FROM AUTHOR]

A new monoraphid diatom species Achnanthidium gladius sp. nov. is described from Indonesia. The description is based on molecular data (18SV4), morphological analysis and comparison with similar species. According to molecular data, Achnanthidium gladius sp. nov. is closely related to Achnanthidium minutissimum. Morphologically, the new species differs from similar species by the absence of a fascia on raphe valve, cell size, and striae density and pattern. The new species is only known from the type locality in Indonesia. Comparison with close related species is given. [ABSTRACT FROM AUTHOR]

A new species, Encyonopsis indonesica, is described from the ancient lake Matano, Sulawesi island, Indonesia. The morphology of this species was studied by means of light and scanning electron microscopy. E. indonesica has a remarkable valve ultrastructure. The valve surface is ornamented with numerous longitudinal siliceous ribs and siliceous verrucae. Valve face delineated from the mantle by a thickened marginal ridge. Raised sterna border the raphe branches. Raphe is distinctly undulate with distal ends hooked strongly to the ventral side. The only similar species to E. indonesica is Amphora dissimilis described from New Caledonia. Comparison of both taxa is given and A. dissimilis is transferred to Encyonopsis. The taxonomic placement of both taxa is evaluated, and the phenomenon of external siliceous ornamentation is discussed. [ABSTRACT FROM AUTHOR]

A new monoraphid diatom species Achnanthidium tinea Tseplik, Kulikovskiy, Kociolek & Maltsev, sp. nov. is described from Indonesia. The species is described on the basis of molecular and morphological analyses. According to molecular data the new species belongs to the clade that includes strains of Achnanthidium minutissimum, Achnanthidium saprophilum and Achnanthidium digitatum. Morphologically, the new species differs quite significantly from other species of the same genus because of linear-elliptic valves with almost parallel sides and strongly radiate striae and a butterfly-shaped fascia on the raphe valve. The morphology and phylogeny of the new species are discussed, and thoughts on the current state of the taxonomy of the genus Achnanthidium are expressed. Our work shows the importance of using molecular data in diatom systematics and also demonstrates the need to investigate rarely studied regions of our planet. [ABSTRACT FROM AUTHOR]

The first comprehensive morphological investigation of the rare, endemic species Cymbella mirabilis Hustedt from the Malili lake system (Indonesia) was prepared using recent samples. This species was originally described on the basis of a single valve. The species was assigned to Cymbella sensu lato on the basis of its asymmetry about the apical axis. SEM investigation shows that this species has a number of unique features relative to other freshwater cymbelloid diatoms, such as an axial plate and marginal laminae on either side of the valve and pseudoseptum at each end of the valve. In these features C. mirabilis resembles certain species in genera such as Gomphoneis Cleve, Afrocymbella Krammer, Gomphosinica Kociolek et al. and Gomphonema Ehrenberg. The unique combination of features in this taxon suggest it cannot be placed in any known genus within the Cymbellales. Thus, we describe a new diatom genus, Alveocymba gen. nov., however, the taxonomic placement of this new genus remains unclear and requires further investigation. [ABSTRACT FROM AUTHOR]

Deforestation and land‐use change in tropical regions result in habitat loss and extinction of species that are unable to adapt to the conditions in agricultural landscapes. If the associated loss of functional diversity is not compensated by species colonizing the converted habitats, extinctions might be followed by a reduction or loss of ecosystem functions including biological control. To date, little is known about how land‐use change in the tropics alters the functional diversity of invertebrate predators and which key environmental factors may mitigate the decline in functional diversity and predation in litter and soil communities. We applied litter sieving and heat extraction to study ground spider communities and assessed structural characteristics of vegetation and parameters of litter in rainforest and agricultural land‐use systems (jungle rubber, rubber, and oil palm monocultures) in a Southeast Asian hotspot of rainforest conversion: Sumatra, Indonesia. We found that (1) spider density, species richness, functional diversity, and community predation (energy flux to spiders) were reduced by 57–98% from rainforest to oil palm monoculture; (2) jungle rubber and rubber monoculture sustained relatively high diversity and predation in ground spiders, but small cryptic spider species strongly declined; (3) high species turnover compensated losses of some functional trait combinations, but did not compensate for the overall loss of functional diversity and predation per unit area; (4) spider diversity was related to habitat structure such as amount of litter, understory density, and understory height, while spider predation was better explained by plant diversity. Management practices that increase habitat‐structural complexity and plant diversity such as mulching, reduced weeding, and intercropping monocultures with other plants may contribute to maintaining functional diversity of and predation services provided by ground invertebrate communities in plantations. [ABSTRACT FROM AUTHOR]

Many ecosystem functions depend on the structure of food webs, which heavily relies on the body size spectrum of the community. Despite that, little is known on how the size spectrum of soil animals responds to agricultural practices in tropical land‐use systems and how these responses affect ecosystem functioning.We studied land‐use‐induced changes in below‐ground communities in tropical lowland ecosystems in Sumatra (Jambi province, Indonesia), a hot spot of tropical rainforest conversion into rubber and oil palm plantations. The study included ca. 30,000 measured individuals from 33 high‐order taxa of meso‐ and macrofauna spanning eight orders of magnitude in body mass. Using individual body masses, we calculated the metabolism of trophic guilds and used food web models to calculate energy fluxes and infer ecosystem functions, such as decomposition, herbivory, primary and intraguild predation.Land‐use change was associated with reduced abundance and taxonomic diversity of soil invertebrates, but strong increase in total biomass and moderate changes in total energy flux. These changes were due to increased biomass of large‐sized decomposers in soil, in particular earthworms, with their share in community metabolism increasing from 11% in rainforest to 59%–76% in jungle rubber, and rubber and oil palm plantations. Decomposition, that is the energy flux to decomposers, stayed unchanged, but herbivory, primary and intraguild predation decreased by an order of magnitude in plantation systems. Intraguild predation was very important, being responsible for 38% of the energy flux in rainforest according to our model.Conversion of rainforest into monoculture plantations is associated by an uneven loss of size classes and trophic levels of soil invertebrates resulting in sequestration of energy in large‐sized primary consumers and restricted flux of energy to higher trophic levels. Pronounced differences between rainforest and jungle rubber reflect sensitivity of rainforest soil animal communities to moderate land‐use changes. Soil communities in plantation systems sustained high total energy flux despite reduced biodiversity. The high energy flux into large decomposers but low energy fluxes into other trophic guilds suggests that trophic multifunctionality of below‐ground communities is compromised in plantation systems. [ABSTRACT FROM AUTHOR]

Terrestrial animal biodiversity is increasingly being lost because of land-use change 1,2 . However, functional and energetic consequences aboveground and belowground and across trophic levels in megadiverse tropical ecosystems remain largely unknown. To fill this gap, we assessed changes in energy fluxes across 'green' aboveground (canopy arthropods and birds) and 'brown' belowground (soil arthropods and earthworms) animal food webs in tropical rainforests and plantations in Sumatra, Indonesia. Our results showed that most of the energy in rainforests is channelled to the belowground animal food web. Oil palm and rubber plantations had similar or, in the case of rubber agroforest, higher total animal energy fluxes compared to rainforest but the key energetic nodes were distinctly different: in rainforest more than 90% of the total animal energy flux was channelled by arthropods in soil and canopy, whereas in plantations more than 50% of the energy was allocated to annelids (earthworms). Land-use change led to a consistent decline in multitrophic energy flux aboveground, whereas belowground food webs responded with reduced energy flux to higher trophic levels, down to -90%, and with shifts from slow (fungal) to fast (bacterial) energy channels and from faeces production towards consumption of soil organic matter. This coincides with previously reported soil carbon stock depletion 3 . Here we show that well-documented animal biodiversity declines with tropical land-use change 4-6 are associated with vast energetic and functional restructuring in food webs across aboveground and belowground ecosystem compartments., (© 2024. The Author(s).)

The aim of this study was to describe the distribution of hepatitis B virus markers among the autochthonous and immigrant multicultural populations of Riau province, Indonesia, in order to define the groups at risk and their infrastructure. This investigation was part of a large hepatitis B vaccination study. A total of 9701 healthy individuals, aged 5 years or older and living in the urbanised area of Batam, near Singapore, and on the surrounding islands were included. Socio-epidemiological data were collected, blood was drawn, and sera were tested for antibodies to hepatitis B core (anti-HBc) and surface antigen (anti-HBs). Anti-HBc-positive sera were tested against hepatitis B surface antigen (HBsAg). All tests comprised immunoassays from Roche (Germany) using Elecsys 2010. Complete data were available from 9314 subjects. The results showed relatively low prevalences of anti-HBc (a marker of a previous hepatitis B infection) and HBsAg in the 5-year-old chiLdren (5.8 and 1.9%, respectively) that increased continuously with increasing age. High anti-HBs levels (>1000 IU/L) were found in all age cohorts, indicating a lifelong threat of active hepatitis B infection. In conclusion, the transmission profile of hepatitis B appeared to be mainly horizontal (person-to-person) in the highly endemic region studied. Vertical transmission was less than 5%. The horizontal transmission routes included non-sexual activities of life since children <10 years of age also showed considerable infection rates. The results underline the need for catch-up hepatitis B vaccination programs for children and adults.